It depends on your congregation. I'm the youth pastor at a fairly conservative church, and a roulette would be fine. Obviously if you are doing it for kids, perhaps not the most responsible choice.
Rope tricks work great, fire is always awesome, cards tricks that everyone can see are great. Torn and restored stuff. Water to wine could definitely work. If you want to do something with a message, then what was said earlier about escapes are great. You can do something with slush powder (perhaps Russian roulette with water/slush powder?)
I would not worry too much about offending people. If they asked you to perform, then they are not worried. There are a lot of misinformed, (or simply a lack of knowledge on the subject) people who have various ideas of what it is like to do shows for churches. If you have something that you think is questionable, talk to the pastor or error on the side of caution (or respect - ie don't nail things into the pulpit... different story).
You will do great, just do the tricks that you know that work for the size group you have. And of course as with any show, make sure it is age appropriate.
Justin
